Ken Rockwell has posted what I think is one of his most interesting observations on which lens to use for taking a PORTRAIT shot of some.
The post is HERE but the starting point is that we should be standing 15 feet (5 metres) from the subject. That makes a lot of sense to me.
This shot was taken with a 105mm lens on a dSLR and I think part of the reason it works is that the woman has an Asian face, so she can take being nearer to the camera.
The risk is that if the face has stronger features, the result might be rather different.
In the post, Ken Rockwell states which focal length to use to capture just a face, or head and shoulders, or more, and whether you are using a digital camera with a crop factor, or a full frame camera.
Doubly interesting to me is that from a psychological point of view, 15 feet gives a very different vision of reality than closer up does. I like talking to people across a room. Strangely perhaps, I find it quite intimate and feel I can really see what is going on between us. It could be that as an Englishman, my preferred social distance is greater than is that case with some other cultures but somehow I think something else is going on.
On a related but ‘reversed’ topic, I saw an interesting article once about the distortion caused by shooting a subject with a short focal length lens. In this case the subject was a car, and the shot was taken extremely from just a foot or so away, with a wide angle lens. Viewed from a normal view distance the car looked distorted. Viewed from just a couple of inches from the print, the car looked normal. Try it for yourself!
Which leads me to this final comment, which is something I read just a short while ago. I cannot remember where I read it, or I would give the attribution, but the comment went something like “the viewing distance for a photographer is the length of his nose.”